Comparing the effects of static stretching and strengthening in lengthened position on EMG activity of hamstring muscle in patients with chronic non-specific LBP having shortened muscle: a randomised controlled clinical trial

Abstract

Introduction: Stretching and strengthening exercises are commonly used to improve muscle tightness. The objective of this trial was to compare the electromyography (EMG) activities of the shortened hamstring in chronic non-specific LBP patients after 12 sessions of static stretching or strengthening exercise.

Methods: Forty-five patients were randomly allocated to either of three groups. All patients received the heat and transcutaneous electrical stimulation to the low back area. Also, specific interventions for (1) Static stretching group (n = 15), (2) Strengthening of hamstring muscle in its lengthened position group (n = 15) and no extra intervention for (3) Control group (n = 15) were applied. Blinded assessments of EMG of hamstring, disability and pain were undertaken at baseline and 12 sessions of interventions.

Results: No significant difference in change in EMG records due to intervention was found between the three groups (p > .05). Comparing the post-intervention with the baseline results, change in hamstring EMG activity in the three groups was not different significantly (p > .05). Moreover, the result of comparison between groups did not show any significant differences in the mean of secondary outcome measures (pain and disability) either (p > .05).

Conclusions: Neither static stretching nor strengthening exercise in the lengthened position for hamstring muscle tightness significantly affected EMG activity of this muscle.

Keywords:

• Low back pain
• electromyography
• hamstring muscle
• muscle strength
• muscle stretching exercises

Acknowledgements

The authors thank the Kermanshah University of Medical Sciences for grants to support this research (Code: 94217). They also thank the participants of the study for their time and dedication.

Ethical approval

This study was approved by the ethics committee of Kermanshah University of Medical Sciences (reference number: kums.rec.1395.169). All study participants gave full informed written consented to take part.

Disclosure statement

No potential conflict of interest was reported by the authors. No known financial, professional or personal conflicts of interests exist among the researchers.

Additional information

Funding

The study is financially supported by the Kermanshah University of Medical Sciences (No: 94217). We affirm that we have no financial affiliation (including research funding) or involvement with any commercial organisation that has a direct financial interest in any matter included in this manuscript. No conflicts of interest were reported for this study.